Unique index not working with Mongoose / MongoDB

I've got a problem with creating unique indexes using Mongoose / MongoDb and can't get it to work. I'm able to add two documents with the same attribute values when I have set a unique index.

I've tried everything I can think of - restarting (everything) changing the syntax etc.

Code

This is the method that I'm using to save an entity:

  create  : function(entity, definition, successFn, errorFn){

    var model = mongoose.model(entity);
    newModel = new model(definition);

    newModel.save(function(error) {
      if(error){
        if(!errorFn){
          throw error;
        }
        errorFn(newModel);
        return;
      }

      successFn(newModel);
    });
  }...

<<

var Something = new Schema({
  objectId          : ObjectId,
  name              : { type : String, index: { unique: true }}, 
  url               : { type : String, index: { unique: true }},
...etc
mongoose.model('Something', Something);

Mongo output

 [conn1] insert xxxxx.agencies 1526ms
 [conn1] building new index on { name: 1 } for xxxxx.agencies
 [conn1] insert xxxxx.system.indexes exception 11000 E11000 duplicate key error    index: xxxxx.agencies.$name_1  dup key: { : "something" } 4ms
 [conn1] building new index on { url: 1 } for xxxxx.agencies
 [conn1] insert xxxxx.system.indexes exception 11000 E11000 duplicate key error index: xxxxx.agencies.$url_1  dup key: { : "http://www.something.com" } 1ms

When I checked in MongoHub the indexes don't appear, so they don't look like they have been created.

This is a duplicate of this question, but it doesn't have an answer that works for me.